Blanching is a technique of cooking vegetables in boiling water for a short time to preserve structure. Most people make the mistake of overcooking vegetables, causing it to turn soggy and brown.

So how do you blanch?
1. Boil a pot of water.
2. Put vegetables in water.
3. Wait until it turns bright green and wait 30 more seconds. (about 1.5 minutes is good)
4. Remove from water and rinse under cold water.
5. (I like to sprinkle salt to add flavor before serving)

What are good vegetables to blanch?
asparagus, green beans, spinach, broccoli and cauliflower

What shouldn't you blanch?
corn, potatoes...anything that should be soft. Rule of thumb is blanching is ideal for green veggies.

Lid covered or open?
don't close the lid. It should be able to vent out the acids and other compounds into the air to keep it green. By preventing the acids from escaping, it builds up in the water and attack the chlorophyll.

What happens when you boil vegetables longer?
the cell structure breaks down too much and goes from firm and tender to mushy. Next the Mg in the center of the chlorophyll escapes and is replaced by H+, causing it to turn from green to brown. During the minute and half of boiling, the chloroplasts near the surface burst and release the green pigment across the tissue, making it bright green. The chlorophyll begin initial breakdown and the alkaline substances dissolve out, removing the bitter and grassy taste. All it takes is a minute and half of boiling to drastically change the taste of broccoli.

Why rinse it in cold water?
there is still lots of residual heat which continue to cook and break down the vegetables. Sometimes it looks great off the pan, but by the time you serve it, the color changes to brown.


Yang said...

Wow, very scientific cooking

Steven said...

Great write-up Tom. Thanks!